The present invention relates generally to fluid delivery systems, to fluid delivery devices and to methods of fluid delivery, and, especially, to fluid delivery systems of hazardous medical fluids, devices for use therein and to methods of delivering hazardous medical fluids to a patient. Current angiographic practice uses X-ray imaging to visualize the inside of the body. Physicians deftly maneuver catheters to a desired blood vessel. X-ray absorbing contrast is injected so that the vessel and downstream vessels can be clearly seen on the X-ray display or film. Using the resultant image, a physician makes a diagnosis and determines appropriate treatment. In interventional procedures, treatment is performed using injection catheters, atherectomy devices, stents, or any one of many interventional devices. Often the interventional treatment is performed during the angiographic procedure, although sometimes treatment is performed at a later time.
During normal angiographic procedures, in addition to contrast it is common to inject saline to flush contrast from the catheter, to keep the catheter lumen open (unclotted), and/or to act as a fluid path for measuring blood pressure. Often the doctor performs the injections by hand, particularly for coronary injections. In some cases, saline is gravity fed.
For peripheral injections, and sometimes for coronary injections, powered injectors are used to inject the contrast because of its high viscosity and the high pressures required to drive contrast through small catheter diameters. Powered injectors can, for example, develop pressures up to 1200 psi in such injections. The pressure range used in such injections is well above the pressure a person can practically develop via hand injection. U.S. Pat. Nos. 5,494,036, 6,339,718, 5,843,037, 5,840,026, 5,806,519, 5,739,508, and 5,569,181, assigned to the assignee of the present invention, which are incorporated herein by reference, disclose the use of powered injector systems that are capable of injecting contrast, saline, and other fluids, either at the same time or in sequence.
In thrombolytic therapy, a doctor places a catheter to study a blockage of a vessel. The doctor then uses a plain catheter or one of many special thrombolytic catheters to inject a thrombolytic agent into the clot. Sometimes the injection is performed using periodically pulsed high-pressure injections to drive the thrombolytic agent into the clot and speed its breakdown. Examples of injectors suitable for use in thrombolytic procedures include the Pulse*Spray Injector Model PSI-1 available from AngioDynamics of Queensbury, N.Y. and the Pulse Thrombolytic Pump PTP1 available from Linet Compact s.r.o. of the Czech Republic.
A difficulty with such currently available injection devices is the requirement that the doctor manipulate the fluid path, sometimes having to disconnect the manual contrast injection syringe and connect the thrombolytic injector. This manipulation takes time, and carries some risk of operator error, including inadvertent biological contamination.
Another interventional procedure under development involves the injection of gene therapies. The goal of one type of gene therapy is to cause the heart muscle to express a gene that causes growth of new blood vessels to nourish heart muscle in which supply arteries have become significantly narrowed by disease. In one type of such gene therapy, the gene therapy DNA is contained in a non-replicating virus. When injected into the body, this virus transfects cells with the contained DNA. As the virus does not contain the DNA required for replicating the virus, it does not multiply and cause disease. These viruses can transfect any cells that they contact with the gene therapy DNA. For this reason, it is important to ensure that the vector viruses are delivered to target tissues only, and to make sure that the hospital personnel are sufficiently protected from contact with the vector virus.
Another application of gene therapy is to block angiogenesis as a way to reduce tumor growth. In this application it is also important that the gene therapy be delivered to the target tissue and that delivery to healthy tissue and health care workers be minimized. There are also many other gene therapy applications under study, for example treating cystic fibrosis and muscular dystrophy.
In a representative procedure using an adenovirus gene therapy product, practitioners perform the following steps: (1) storing frozen vials in the pharmacy; (2) in a pharmacy hood, using gloves and proper technique, thawing the bottle with the gene therapy drug in the hand, avoiding agitation; (3) using a needle, pulling a few ml of drug into a hand syringe, for example a 10 ml syringe; (4) adding a few ml of saline to dilute the drug; (5) placing the hand syringe in a syringe holder for transport to the interventional suite to preserve the sterility of the outside of the syringe (the thawed drug has to be used within several hours); (6) for use in the interventional suite, donning goggles and masks (doctors, nurses, technicians) with M-95 filters to protect against infection from airborne viruses; (7) purging the fluid lines of air; (8) diluting the drug further if needed; (9) positioning the catheter in the desired vessel using normal angiographic equipment (manifolds, catheters, guidewires) and technique (normally this is a deep subselective placement to avoid any reflux of contrast or drug into the aorta, where it would be distributed systemically); (10) verifying the placement of the catheter with a contrast injection; (11) optionally flushing the manifold and/or catheter with saline by removing the contrast syringe and attaching the saline syringe; (12) disconnecting the saline syringe; (13) connecting the gene therapy syringe; (14) injecting by hand approximately 1 to 5 milliliters of the gene therapy drug over 1 to 2 minutes; (15) disconnecting the gene therapy syringe; (16) connecting the saline syringe; (17) injecting a few mil of saline over the same time period (e.g., 1 to 2 minutes) to flush the gene therapy drug out of the fluid path and into the patient; (18) disconnecting the saline syringe; (19) reconnecting the contrast syringe; (20) injecting contrast to confirm that the catheter has not moved; (21) repositioning the catheter for the next injection; (22) repeating prior steps until all vessels are injected; and (23) disposing of the disposable parts of the systems (as biohazardous material).
There are a number of drawbacks or unmet needs with the current systems and processes for gene therapy delivery. For example, an enclosed preparation hood is required.
Furthermore, disconnecting and reconnecting multiple syringes for delivering contrast, saline, and drugs is time consuming and increases the risk that some of the drug may be spilled or aerosolized and thus infect the operator and/or the patient in an undesired fashion, or that the drug may be contaminated.
Moreover, it is very difficult for a human to inject a fluid at a steady rate, especially for slow rates (ml/min) extending more than a minute. Motion at a slow rate suffers from stick-slip friction in the syringe, and it takes significant concentration to do it for two 1-2 minute periods up to five times in a procedure. There is significant risk of accidental jerking or bolus injection that either wastes drug or causes it to reflux into the aorta and travel elsewhere in the body. Also, as syringes are connected and disconnected, the plunger can be unintentionally bumped and a bolus of drug injected into the patient or expelled into the environment. Additionally, the changeover time from drug syringe to saline syringe causes an uncontrolled break in therapy injection. As the drug is susceptible to clump formation if agitated, manually connecting and disconnecting the syringe provides opportunities for agitation and clumping.
As mentioned, deep sub-selective catheter placement is needed to avoid drug reflux into the aorta. However, such catheter placement introduces the risk of reducing blood flow through that artery and increases the possibly of causing dissections. Moreover, deep sub-selective catheter placement is more difficult technically to achieve.
Multiple manual manipulations of syringes and the manifold connected to the catheter in the patient increases the risk that the catheter position will be accidentally shifted from optimum placement.
Multiple manual manipulations also increases the risk of errors, such as injecting saline first, and then the drug, and thus having the drug in the catheter being injected into the aorta when it is being moved from one vessel to another.
All procedures that provide access to a patient's blood vessels require that a sterile field be created and maintained to protect the patient against infections. Operators with sterile gloves cannot touch anything that is not sterile, and operators with non-sterile gloves cannot touch anything that goes into the sterile field. In addition, anything that touches the patient, and especially anything that touches bodily fluids, such as blood, has to be disposed of as a biohazardous material. And, as mentioned above, the gene therapy drug itself, even when uncontaminated, poses a biohazard.
Similarly, aerosolization or spillage of chemotherapy agents during preparation or delivery can create hazardous conditions for health care workers or nearby people. Preparation of chemotherapy agents is generally done in a pharmacy in a hood, to protect the pharmacy workers. Chemotherapy agents can be administered intra-arterially into the vessels supplying nourishment to tumors. This has the benefit of giving the tumor a very high dose while keeping the total systemic dose (and thus tissue damage and side effects) to a minimum. It has the downside of requiring the occupation of the expensive facilities of a catheterization or special procedures suite. More commonly, chemotherapy drugs are administered through peripheral intravenous catheters, PICC lines, central venous catheters, or infusion ports. The drug in injected with a hand syringe or an infusion pump, often into a side port of an infusion line connected to one of the venous access devices mentioned above. It is commonly done in the patient's room, an outpatient clinic, or more recently in the patient's home. The making and breaking of connections provides the opportunity for drug spillage or aerosolization and thus transmission to nearby personnel. In chemotherapy administration masks and goggles are not routinely used.
With intra-arterial administration of chemotherapy, the tumor receives the drug directly. With intra-venous administration, many chemotherapy agents damage the veins in which they are injected. This causes local reactions and pain, and it makes it difficult for health care workers to subsequently be able to insert a catheter into the vein.
A third situation which can involve the delivery to a patient of potentially hazardous drugs with associated concern about exposure of other personnel are intramuscular and subcutaneous injections. There are many clinical trails and much research being focused on intramuscular injection of gene therapies and biologics. The needle of a hand syringe is inserted through the skin into the target muscle. Then a controlled amount of drug is injected. Each time the needle is removed from one site and moved to another there is the opportunity for aerosolization and/or spillage since the drug is present at the needle tip.
While it is not yet widely done for gene therapies, inhalation of drugs is a common practice for asthma drugs, is being studied for other drugs, and is another application in which nearby personnel can inadvertently be contaminated by the drug being administered to a patient. As more potent drugs are administered this way, the effects of accidental exposure will become more prevalent. In this case, the drug is intentionally delivered as an aerosol of a liquid or a power, so the problem is particularly severe. All of the aerosol that is put into the air conduits and the patient's airways is not deposited in the patient's body. Thus there is a significant amount of aerosol that could be accidentally released.
It is desirable to develop systems, devices and methods of delivering or administering hazardous pharmaceuticals to patient that reduce and/or eliminate one or more of the problems with current systems, devices and methods described above as well as other problems.